Since CDs (Compact Discs) are easy to produce, inexpensive, and easy to handle, they have widespread as mediums for storing various types of data such as digital audio data and video data, computer programs, and so forth.
In recent years, as the performance of personal computers has been improved and a CD-R (CD-Recordable) disc and a CD-RW (CD-Rewritable) disc have come out, digital data recorded on for example a CD-DA (CD-Digital Audio) disc can be easily copied. This copying operation is illegal because it disregards copyright of the digital data. Thus, it is necessary to protect copyright of digital data recorded on the CD.
From such a point of view, as new mediums, a DVD-Audio (Digital Versatile Disc-Audio) disc, an SACD (Super Audio CD) disc, and so forth have been standardized so that permission or prohibition for their copy operations can be designated. However, since the formats of the DVD-Audio disc and SACD disc are not compatible with the format of the CD, the new mediums require their dedicated drive devices. They prevent these discs to become widespread.
Thus, a recording medium, a recording method or a reproducing method, and a recording apparatus or a reproducing apparatus that provide security, namely a copyright protecting function while having compatibility with a conventional drive device are desired. However, if these mediums have compatibility with a conventional drive device, their copyright protection function will not work. Thus, data that is read from such a recording medium can be directly copied to a CD-R disc or a CD-RW disc.
In addition, there is a need to read a part of data from for example a DDCD (Double Density CD) on which the data has been recorded with ECC (Error Checking and correcting Code) using a conventional CD drive device. However, the need has not been satisfied from a view point of copyright protection.
From the foregoing point of view, the present invention provides a CD that has high compatibility with a conventional CD and prevents its contents from being illegally copied. In the following description, it is assumed that a CD includes a CD-DA and a CD-ROM.